Hard disk drives are booming with digital devices, such as digital cameras and audio/video devices and even television sets, which require a large amount of storage. Thus, there is a huge market demand for the HDDs, which drives the development of the HDDs in two aspects, namely high areal density and small physical volume.
The HDD comprises a plurality of disks each having a surface on which a magnetic coating is formed for recording digital data therein. A magnetic read/write slider is movable across the magnetic surface of the disk to access data stored therein. High areal density of record can be accomplished by either improving performance of the magnetic coating on the disk surface or reducing the size of the magnetic read/write slider that access data stored in the magnetic coating. Size reduction of the read/write slider means read/write signal is weaker and thus the magnetic track width and/or the magnetic track pitch can be decreased accordingly. However, the key aspects of decreasing the magnetic track width and/or track pitch is to improve the position control of the read/write slider, such as the flying height control, which represents the distance between the disk surface and the read/write slider when the slider is moving across the disk surface, also thickness of protective coating for both the magnetic slider and the disk surface, slider pole tip recession, and so on.
On the other hand, to minimize the physical volume of the HDD is a systematic engineering, which concerns not only changes in the physical dimension of parts of the HDD, but also re-optimization of flying dynamics performance of the slider. Currently used HDDs are 3.5″ for desktop computers, and 2.5″ for notebook computers. For applications in portable digital audio/video device, the size of the HDDs is down to 1″ or even 0.85″.
The magnetic read/write slider is the key component of the HDD. The magnetic read/write slider comprises a ceramic housing that controls the flying altitude or height of the slider. On a surface of the ceramic housing, patterns, such as “landing pad” and “flying rail” and negative pressure cavity, are formed by for example depositing and etching. The magnetic read/write slider also comprises functional layers arranged on the ceramic housing. The functional layers include transducers or magnetic pole tips, and read/write wire connecting pads or bonding pads.
The magnetic read/write slider has a very flat surface on the magnetic pole tip. The flat surface is conventionally formed by lapping the housing of the magnetic read/write slider with ultra-thin diamond slurry, having a nominal diameter of 50-100 nm. The very flat surface of the slider has a roughness, Ra, less than 0.3 nm. The lapping process also helps minimizing the pole tip recession.
For small-sized HDD, which is often referred to as micro-drive, the surface roughness for the slider housing must be increased, namely having a rougher housing surface, in order to improve performance of take-off and touch-down for the magnetic read/write slider. The slider housing is generally made of AlTiC, which is a mixture of Al2O3 (alumina) and TiC (titanium carbide), containing island-like TiC grains embedded in Al2O3 matrix.
U.S. Pat. Nos. 5,010,429 and 5,052,099 teach using sputtering process to form the rough surface for the slider housing. The target height, which is measured from top to bottom, of the roughness of the slider housing is about 50-300 angstrom, and the peak (protruded area) width and the peak-to-peak distance is about 5-20 micrometers. This is not good enough for micro-drive applications and the present invention is aimed to provide an improved micro-texture on the ABS of a magnetic read/write slider, which in turn improves the flying performance of the slider.